1. Field of the Invention
The present invention relates to an electronic apparatus. In particular, the invention relates to an electronic apparatus that is equipped with a solar panel and receives GPS radio signals to correct time.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2010-96707 discloses a timepiece which utilizes the Global Positioning System (hereinafter referred to as a “GPS timepiece”). The GPS timepiece is one of the electronic apparatuses capable of precisely correcting time anywhere in the world.
The GPS timepiece uses a global positioning system, i.e. a GPS receiver, which receives radio signals (hereinafter referred to as “GPS radio signals”) sent from artificial satellites (GPS satellites) orbiting the Earth in space and determines the location of the receiver, so as to acquire correct time information superimposed on the GPS radio signals and correct the time.
The GPS radio signal is composed of circularly polarized microwaves. An antenna that is the most suitable for receiving such microwaves is a patch antenna, which is small and has excellent reception characteristics.
Electronic apparatuses equipped with solar panels that convert light into electricity are also widely known.
Such electronic apparatuses provided with solar panels can be used for long terms without the replacement of secondary batteries that can accumulate the electricity generated by the solar panels.
GPS timepieces equipped with solar panels are easy to handle and convenient for users because the GPS timepieces no longer require the users to correct time and replace the batteries.
A typical solar panel includes a metal electrode, a semiconductor layer, and a transparent electrode, which are formed of a conductive material, such as an aluminum conductor.
If a solar panel is disposed above an antenna, antenna characteristics (radio signal reception characteristics) are degraded significantly due to the influence of the conductive material.
To avoid this disadvantage, a configuration for preventing such degrading in antenna characteristics is proposed in Japanese Unexamined Patent Application Publication No. 2012-211895 in which a solar panel has a cutout at a portion facing an antenna so that no solar panel is disposed above the antenna.
Unfortunately, this configuration impairs design versatility because the cutout portion of the solar panel is easily seen through a dial plate, although the configuration can keep satisfactory antenna characteristics.